Year	Percent
1990	73.27
1991	71.87
1992	73.19
1993	73.72
1994	74.72
1995	75.29
1996	76.43
1997	76.67
1998	77.66
1999	78.61
2000	78.68
2001	78.26
2002	79.15
2003	79.95
2004	81.37
2005	81.7
2006	82.13
2007	82.01
2008	82.05
2009	82.85
2010	83.32
2011	83.23
2012	83.87
2013	84.06
2014	84.48
2015	85.48
2016	85.61
2017	85.13
2018	85.1
2019	85.61